Circulatory process for treatment of hydrocarbons with in situ production of hydrogen



Uni d SW68. aI TQ CIRCULATORY PROCESS FOR TREATMENT OF HYDROCARBONS WITHIN SITU PRODUCTION a or HYDROGEN l'rentiss S. Viles, Baytown, Tex.,assignor, by mesne assignments, to Esso Research and Engineerin Company,Ehzabeth, N.J., a corporation of Delaware :Application May 28, 1956,Serial No. 587,699 9 Claims. 01. 208-60) of'hydrocarbons with hydrogenin which only hydrocarbon is added to the system in which thehydrocarbon is treated. i i i I The present invention may be brieflydescribed as a method for treating hydrocarbons in a circulatory systemin which a stream of feed hydrocarbon is formed.

The stream is contacted with a hydrocarbon conversion catalyst in afirst reaction zone at a temperature within therange of 500 to 1200 F.and at a pressure in the range of 15 to 900 pounds per square inchgauge. By

contact with the hydrocarbon conversion catalyst a liquid hydrocarbonproduct is formed and a first gaseous product containing hydrocarbons isalso formed. The first gaseous product is then contacted with a cobaltmolybdate catalyst in a second reaction zone at a temperature within therange of 850 to 1600 F. to form a second gaseous product which containshydrogen and which is substantially free of hydrocarbon. The secondgaseous product is admixed with the feed hydrocarbon tq-form the streamand a normally gaseous hydrocar- Ben is added to the system ahead of oneof said reaction zones, liquid product being withdrawn from the system..;.The normally gaseous hydrocarbons may suitably be natural gas and thecomponents thereof. Specifically, therlormally gaseous hydrocarbons maycomprise or include methane, ethane, propane, the butanes, ethylene,propylene, the butylenes, the diolefins, such as butadienes,.and thelike. While mixtures of these hydrocarbons may be used, it may sometimesbe preferred and it is contemplated that it is within the purview ofthis: invention to use purified hydrocarbons, such as methane, ethane,or propane. Natural gas hydrocarbons such as methane and ethane will bepreferred.

-The hydrocarbon feed stock of the present in vention may includefractions boiling in the range from. aboutv 100 up to about 1000" F.Suitably the hydrocarbon feed stocks are the normally liquidhydrocarhens and may include gasoline, kerosene, gas oil, heating0i1,--.components thereof, and mixtures of components of these severalfractions. Crude petroleum may be charged to the process of the presentinvention but it; will be preferred to charge the crude residue afterremoval of the lighter and more volatile fractions there-- from. It iscontemplated in the practice of the present invention that hydrocarbonshaving a low hydrogen to carbon. ratio will form a preferred feed stockof the present invention.

The hydrocarbon conversion operation of the present invention mayinclude any hydrocarbon conversion whercinthe hydrocarbon is contactedat an elevated temperature withv hydrogen. Such. processes may includethe so-called hydrofining, hydrocracking, hydrogenation, and the like,operations. Such hydrogen treatment processes may suitably be conductedat a temperature in the range from about 500 to about 1000 F. with apreferred temperature range from about 600 to about 900 F.

Pressures may suitably range from about 15 to about 900 pounds persquare inch gauge with a preferred range from about 15 to about 600pounds per square inch gauge.

The hydrocarbon conversion catalyst may suitably be any hydrocarbonconversion catalyst which is employed in the hydrogen treatment ofhydrocarbons, such as petroleum hydrocarbons. Illustrative of suchconversion catalysts may be mentioned the metals, oxides and sulfides ofchromium, nickel, molybdenum, cobalt, platinum, palladium, tungsten,titanium, and the like. These catalysts may be employed as mixtures; forexample, the hydrocarbon conversion catalyst may be molybdenum oxide,sulfide, cobalt molybdate, which is a mixture of cobaltous oxide andmolybdic trioxide, platinum as the metal or as compounds of the metal,nickel and tungsten sulfide, and mixtures thereof, and the like.

The catalyst employed in the second reaction zone of the presentinvention is suitably cobalt molybdate which is a mixture of cobaltousoxide and molybdic trioxide. The cobaltous oxide and molybdic trioxidemay be em:- ployed in a preferred ratio of mole per mole as the catalystin the second reaction zone but the ratio of cobaltous oxide to molybdictrioxide may range from 0.1:1 to 1:01 of cobaltous oxide per mole ofmolybdic trioxide.

Both the hydrocarbon conversion catalysts and the cobalt molybdate usedin the second reaction zone of the present invention may suitably beemployed as a supported catalyst. For example, the hydrocarbonconversion catalyst may be supported on a suitable support in an amountin the range from about 1.0 to about 50.0 weight percent but with apreferred amount of approximately 15.0 weight percent of the catalyst.

The amount of cobalt molybdate on the support used in the secondreaction zone may range from about 1.0 to 25.0 weight percent with apreferred amount of approximately 15.0 weight percent of the totalcatalyst. Suitable supports for the catalyst employed in the firstreaction zone and the second reaction zone may include alumina,zirconia, magnesia, silica, silica-alumina, Filtrol kieselguhr,Floridan, and the like. Preferred supports are pure alpha and gammaalumina.

In the first reaction zone where the hydrocarbons are converted, thehydrocarbons may contact the hydrocarbon conversion catalyst at spacevelocities in the range from about 0.5 to about 15 v./v./hr. Somevariations in the space velocities within the range given arepermissible depending on the feed stock. With gas oils, space velocitiesfrom about 0.5 to about 5 v./v./hr. are particularly useful while withnaphthas space velocities from about 1 to about 10-v./v./hr. may beused. With crude petroleum residues and other asphaltic-containing' feedstocks, space velocities from about 0.25 to about 5 v./v./hr. aresuitably used.

In the second reaction zone of the present invention the gaseous productcontacts the catalyst at a suitable space velocity which may range fromabout 1 to about 500 volumes of gaseous product per volume of catalystper hour, with a preferred space velocity from about"-50 tacted with thecatalyst in the vapor phase.

The pressures employed in the second reaction zone of the presentinvention may range from about pound absolute to about 1000 pounds persquare inch gauge with a preferred pressure of about atmospheric.Lowpressures are desirable and give the most satisfactory results in thesecond stage of the present invention.

The reaction zones of the present invention may be arranged with thecatalyst provided as a fixed bed or the reaction may be conducted ineither or both of the reaction zones employing the so-called fluidizedpowder technique wherein the catalyst is suspended in vaporizedhydrocarbons. The reaction may be conducted in either the first orsecond reaction zones or both in a suspension or slurry of the catalystin the hydrocarbons.

The persent invention is quite advantageous and useful in thathydrocarbons are treated with hydrogen in a circulatory system whereonly hydrocarbons are added and a normally gaseous hydrocarbon, thehydrogen being produced in situ from the gaseous products produced inrfllCPI'OCCSS and from the added gaseous hydrocarbons, if desired. Thegaseous hydrocarbons where employed in the practice of the persentinvention may be added into the circulatory system either with the feedstock or prior to the contacting of the gaseous hydrocarbon product fromthe first operation with the catalyst in the second reaction zone. Byoperating in this manner, the only material withdrawn is the liquefiedproduct and the only added components are hydrocarbons both liquid andnormally gaseous.

The invention will be further illustrated by reference to the drawing inwhich the single sheet is in the form of a flow diagram of a preferredmode.

Referring to the drawing, numeral 11 designates a charge line throughwhich a liquefied hydrocarbon feed such as a crude residue containingasphaltic components is introduced into the system and then introducedby way of line 12 into a heater or furnace 13 provided with heating coil14 and heating means illustrated by burners 15.

The heated and at least partially vaporized hydrocarbon feed is thendischarged by way of line 16 into line 17 where it admixes with ahydrogen-containing gas flowing in line 17 from a source which will bedescribed further. The heated hydrocarbons and hydrogen-containing gaspass into a first reaction zone 18 containing a bed 19 of a hydrocarbonconversion catalyst which may be a platinum-containing catalyst or amolybdenum-eontaining catalyst, such as cobalt molybdate. In reactionzone 19 conditions are maintained to convert the hydrocarbons or toremove sulfur and deleterious compounds and the like from thehydrocarbons or to increase the hydrogen to carbon ratio of thehydrocarbons as may be desired. The converted hydrocarbons then issuefrom reaction zone 18 by way of line 20 and are discharged thereby intoa separation zone 21 wherein a separation is made between the normallygaseous product which contains hydrocarbons and the liquid product.

The liquid product is withdrawn from separation zone 21 by line 22 andis discharged into a distillation zone 23 which, for purposes ofillustration, is shown as a single distillation tower. It is to beunderstood, however, that distillation zone 23 may suitably include aplurality of fractional distillation towers equipped with all auxiliaryequipment necessary for precise separation among the various componentsof the product introduced by line 22. Such auxiliary equipment mayinclude vaporliquid contacting means, such as hell cap trays, suitablepacking and the like and will include means for inducing reflux andcooling and condensing means. In anyevent, the conditions indistillation zone 23 are adjusted by heating means illustrated by steamcoil 24 to adjust temperature and pressure conditions in zone 23 forremoval of light products by line 25, intermediate products by lines 26and 27, and heavier fractions by line 28. The fractions recovered bylines 25, 26, and .27 maybe further processed and may suitably be usedas motor fuel components of high octane number.

The gaseous products are separated in separator 21 from the liquidproducts and withdrawn by line 29 controlled by valve 30 and introducedinto line 31 for contacting with cobalt molybdate catalyst in reactionzone 32 arranged as a bed33 therein. Under the conditions .in which thegaseous product contacts the catalyst in reaction zone 32, thehydrocarbons therein are substantially completely converted to hydrogen.The gaseous product from reaction zone 32 is withdrawn therefrom by line17 and introduced thereby into reaction zone 18 in admixture with thehydrocarbons in line 16.

Since the gaseous product in line 29 may contain impurities, such ashydrogen sulfide, ammonia and water, it may suitably be treated byrouting all or part of the gases in line 29 through a scrubbing zonegenerally indicated by the numeral .34, the gases being introduced intozone 34 by line 35 controlled by valve 36, valve in line 29 either beingpartly or completely closed. In scrubbing zone 34 the gaseous mixturecontacts a scrubbing solution such as aqueous monoor diethanol amine,and the like, introduced thereto by line 37 controlled by valve 38. Theused or spent scrubbing solution is discharged from zone 34 by line 39controlled by valve 40 for revivification or regeneration in means notshown for re-use in zone 34. The scrubbed gases which may compriseessentially methane and the like are discharged by line 41 controlled byvalve 42 into line 29 and thence into line 31.

Since the gas in line 17 may not contain a suificient amount of hydrogenin accordance with the present invention, natural gas or methane, andthe like, may be introduced into line 30 by way of line 43 controlledvalve 44. The natural gas or components thereof on pas sage through thereaction zone 32 are substantially coin} pletely converted to hydrogenunder the conditions set out hereinbefore.

Likewise, natural gas may be introduced with the feed hydrocarbons inline 11 and then pass into heater 13, Provision is made for introducingsuch natural gas by line 45 controlled by valve 46.

It will be seen from the foregoing description taken with the drawingthat an improved method for treating hydrocarbons with hydrogen has beenprovided in that the only components added to the system arehydrocarbons which will include both liquid and normally gaseoushydrocarbons. Thus, in accordance with the present invention, a methodis provided whereby high hydrogen to carbon ratios normally gaseoushydrocarbons, such as methane, ethane, propane and the like, may becombined with low hydrogen to carbon ratio hydrocarbons, such ascruderesidua, reduced crudes, asphaltic fractions, and the like, to producehydrocarbon fractions having a-higher hydrogen to carbon ratio than theliquid hydrocarbon feed stock. These higher and more desirable hydrogento carbon ratio fractions may include gasoline, middle distillates, suchas heating oils, lubricating oils and the like.

Also in the present invention a method is provided for removal ofundesirable contaminants, such as sulfur, nitrogen, oxygen, andundesirable metallic compounds frequently encountered in crude residuesand the like;- This is accomplished by treating such hydrocarbon fractions with hydrogen whereby the deleterious compounds are converted and/or placed in a condition whereby they may be readily removed.

In the second stage of the present invention. it is" essential thatcobalt molybdate or a mixture of CObHltOllSf oxide and molybdic trioxidebeemployed sincecatalyst under conditions set out hereinbeforeselectivelyconverts hydrocarbons to hydrogen forming a substantiallypure hydrogen under the selected conditionsr The present invention isalso desirable in that in the-cit culatory; system the reactionzonewhere the hydtoc'arbons are converted may be sized for the passageand contact of the hydrocarbons in admixture with the hydrogen formed inthe process wherein the second reaction zone will be of smaller size byvirtue of the passage of only the gaseous product from the firstreaction zone therethrough together with any added natural gas or thelike. Suitably the size of the first reaction zone to the size of thesecond reaction zone may be in a ratio in the range from about 100:1 toabout 5:1.

Another advantage of the present invention is that the hydrogen producedin the present invention is produced in a heated condition and does nothave to pass through the heater 13 since the second reaction zone maysuitably be at a higher temperature than the first reaction zone.

Many modifications of the present invention may be performed withoutdeparting from the spirit and scope of the claims.

This application contains subject matter common to an applicationentitled Method of Making Hydrogen, sleirial No. 587,566, filed May 28,1956, for Prentiss S.

The nature and objects of the present invention having been completelydescribed and illustrated, what I wish to claim as new and useful and tosecure by Letters Patent is:

1. In a circulatory system in which a normally liquid low hydrogen tocarbon ratio hydrocarbon is contacted with a cobalt molybdate catalystin the presence of hydrogen at a temperature within the range of 500 to1000 F. and at a pressure within the range of 15 to 900 pounds persquare inch gauge in a first reaction zone and in which normally gaseousand normally liquid hydrocarbon products are formed, the methodincluding the step of contacting said normally gaseous product with acobalt molybdate catalyst in a second reaction zone at a temperaturewithin the range of 850 to 1600 F. whereby said hydrogen is formed fromsaid gaseous hydrocarbon product and only hydrocarbons are added to thesystem.

2. A method in accordance with claim 1 in which a normally gaseoushydrocarbon is added to said gaseous hydrocarbon product prior tocontacting same with said catalyst in said second reaction zone.

3. A method in accordance with claim 1 in which a normally gaseoushydrocarbon is added to said normally liquid hydrocarbon prior tocontacting same with said catalyst in said first reaction zone.

4. In a circulatory system in which a normally liquid hydrocarbon iscontacted with a low hydrogen to carbon ratio hydrocarbon conversioncatalyst in the presence of hydrogen at a temperature within the rangeof 500 to 1000 F. and at a pressure within the range of 15 to 900 poundsper square inch gauge in a first reaction zone and in which normallygaseous and normally liquid hydrocarbon products are formed, the methodincluding the step of contacting said normally gaseous product with acobalt molybdate catalyst in a second reaction zone at a temperaturewithin the range of 850 to 1600 F. whereby said hydrogen is formed fromsaid gaseous hydrocarbon product and only hydrocarbons are added to thesystem.

5. In a circulatory system in which a normally liquid low hydrogen tocarbon ratio hydrocarbon is contacted with a platinum-containingcatalyst in the presence of hydrogen at a temperature within the rangeof 500 to 1000 F. and at a pressure within the range of 15 to 900 poundsper square inch gauge in a first reaction zone and in which normallygaseous and normally liquid hydrocarbon products are formed, the methodincluding the step of contacting said normally gaseous product with acobalt molybdate catalyst in a second reaction zone at a temperaturewithin the range of 850 to 1600 F. whereby said hydrogen is formed fromsaid gaseous hydrocarbon products and only hydrocarbons are added to thesystem.

6. In a circulatory system in which a normally liquid low hydrogen tocarbon ratio hydrocarbon is contacted with a molybdenum-containingcatalyst in the presence of hydrogen at a temperature within the rangeof 500 to 1000 F. and at a pressure within the range of 15 to 900 poundsper square inch gauge in a first reaction zone and in which normallygaseous and liquid hydrocarbon products are formed, the method includingthe step of contacting said normally gaseous product with a cobaltmolybdate catalyst in a second reaction zone at a temperature within therange of 850 to 1600 F. whereby said hydrogen is formed from saidgaseous hydrocarbon product and only hydrocarbons are added to thesystem.

7. A circulatory method for treating low hydrogen to carbon ratiohydrocarbons in a circulatory system in which only hydrocarbons arecharged which comprises establishing a stream of a liquid feedhydrocarbon, contacting said stream with a hydrocarbon conversioncatalyst in a first reaction zone at a temperature within the range of500 to 1000 F. and at a pressure within the range of 15 to 900 poundsper square inch gauge to form a normally liquid hydrocarbon product anda first normally gaseous product containing hydrocarbon, contacting atleast a potion of the first normally gaseous product with a cobaltmolybdate catalyst in a second reaction zone at a temperature within therange of 850 to 1600 F. to form a second gaseous product containinghydrogen and substantially free of hydrocarbon, admixing said secondgaseous product with said feed hydrocarbon to form said stream, adding anormally gaseous hydrocarbon to said system ahead of one of saidreaction zones, and withdrawing said liquid product from said system.

8. A method in accordance with claim 7 in which the i normally gaseoushydrocarbon is added to the feed hydrocarbon.

9. A method in accordance with claim 7 in which the normally gaseoushydrocarbon is added to the first gaseous product.

References Cited in the file of this patent

1. IN A CIRCULATORY SYSTEM IN WHICH A NORMALLY LIQUID LOW HYDROGEN TOCARBON RATIO HYDROCARBON IS CONTACTED WITH A COBALT MOLYBDATE CATALYSTIN THE PRESENCE OF HYDROGEN AT A TEMPERATURE WITHIN THE RANGE OF 500* TO1000* F. AND AT A PRESSURE WITHIN THE RANGE OF 15 TO 900 POUNDS PERSQUARE INCH GAUGE IN A FIRST REACTION ZONE AND IN WHICH NORMALLY GASEOUSAND NORMALLY LIQUID HYDROCARBON PRODUCTS ARE FORMED, THE METHODINCLUDING